Eye-opener: Lateral canthotomy in pigs: A randomised study.

Background Regional Anaesthesia of the eye, including techniques like retrobulbar, peribulbar, and sub-Tenon's block, is essential for a wide range of ophthalmologic surgeries. These techniques carry risks of severe complications as retrobulbar haemorrhage and infraorbital compartment syndrome, potentially entailing vision loss. Lateral canthotomy with inferior cantholysis (LCIC) is a crucial emergency procedure to manage such complications, and its proficiency among clinicians is vital. Objective This study aims to validate a pig-head teaching model by investigating intra-ocular pressure (IOP) variations during simulated intra-orbital haemorrhage and following LCIC procedure. Design Randomised comparative study. Setting Single centre, tertiary university hospital, Berne, Switzerland, January and February 2023. Subjects Thirteen fresh porcine heads from the local abattoir were used to create a model of retrobulbar haemorrhage. Interventions After visual inspection, we injected 25 ml of hydroxyethyl starch to simulate haemorrhage. IOP measurements were taken at baseline (T0), after injection (T1), immediately after LCIC (T2), and 10 min post-LCIC (T3). The LCIC procedure was performed on randomly selected eyes. Spontaneous regression of intra-ocular pressure was studied without LCIC being performed in control eyes. Main Outcome Measures The primary outcome was the difference in IOP trends between the LCIC and control groups. Secondary outcomes included the rate and extent of IOP reduction post-LCIC. Descriptive statistics and repeated measures ANOVA were used to analyse IOP measurements, with posthoc analysis applied where significant differences were found. Results Baseline IOP showed no significant differences between groups. Postinjection IOP increased significantly in all eyes. LCIC resulted in a median IOP decrease of -45.8 mmHg, compared to -20.9 mmHg in the control group (P = 0.002). The target IOP decrease rate of ≥3 mmHg per minute was achieved only in the LCIC group. Discussion LCIC significantly reduced IOP immediately and 10 min postprocedure compared to controls in simulated retrobulbar haemorrhage. The study supports the clinical utility of the LCIC procedure in managing acute orbital compartment syndrome and validates the pig head model as training device of moderate to high fidelity.